Halal Institute NU is the institution established by Nahdatul Ulama’ in 2012 as an institution that has the authority to conduct the certification of halal. But in 2014 the government legitimize the constitution of product halal Guarantee which organize the system of product halal Guarantee in Indonesia, because of the valid constitution, it influence the authority of Halal Institute NU. This research there are three formulations of problem, first, how is the authority of Halal institute NU before the validation of the enactment about product halal Guarantee? Second, how is the authority of Halal institute NU after the validation of the enactment about product halal Guarantee? Third, how is the authority Halal institute NU in review of Maslahah Mursalah?

Focus and purpose of this research is to know the role of Halal institute NU in halal sertification of Indonesia, then to know the authority of Halal institute NU after the validation of constitution about product halal Guarantee. And to know the authority that Halal Institute NU has about review of Maslahah Mursalah. Research methods of this research are types of research which are normative research or library research. Then research approach of this research are statue approach and conceptual approach. Data source of this research is secondary data that is information that obtained through already written in documentary that called referred to the legal materials and descriptive qualitative analysis.

This research conclude that Halal Institute of NU as an institution of halal sertification that has important role to give protection the halal certainty for the Indonesia community by issuing the halal certificate . After the constitution validaty of product halal Guarantee, authority that Halal Institute of NU has to issuing the halal certificate can not be held by this institute again, the role that can be held is for Halal Examiner Institution. In marsalah mursalah review Halal Institute of NU with the authority has provided a real convenience for the general public that the certainty of the status of halal products.